Therapy-related megakaryoblastic leukemia with pituitary involvement following treatment for non-Hodgkin's lymphoma

A case of a 66-year-old Japanese man developed therapy-related megakaryobla stic leukemia with pituitary involvement after chemotherapy for non-Hodgkin 's lymphoma. Alkylating agents had been administered for the treatment of n on-Hodgkin's lymphoma and 6 years later, megakaryoblastic leukemia with mye lofibrosis and myelodysplasia developed. The blast tells expressed CD41, an d immature antigens also. These findings were compatible with therapy-relat ed megakaryoblastic leukemia. An autopsy revealed blast-cell infiltration i nto multiple organs including the posterior pituitary lobe. Therapy-related megakaryoblastic leukemia Is very rare, and pituitary involvement may be a ssociated with immaturity of blast cells.